(19)

(11)

EP 1 368 552 A1

(12)

(43) Date of publication: 10.12.2003 Bulletin 2003/50 (21) Application number: 02718275.7 (22) Date of filing: 15.03.2002

(51) International Patent Classification (IPC)7: E21B 34/10, E21B 23/00, E21B 21/10 (86) International application number: PCT/GB0201/207 (87) International publication number: WO 0207/5104 (26.09.2002 Gazette 2002/39)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR Designated Extension States: AL LT LV MK RO SI (30) Priority: 16.03.2001 GB 0106538 (71) Applicant: ANDERGAUGE LIMITED Aberdeen AB1 4YB (GB)	(72) Inventor: EDDISON, Alan Martyn DrumlithieStonehaven AB39 3YS (GB) (74) Representative: Shanks, Andrew  Cruikshank & Fairweather,19 Royal Exchange Square Glasgow G1 3AE Glasgow G1 3AE (GB)